I'd like to be able to stream video from a camera attached to my computer directly to an FPGA I have attached to my computer via PCIE.

I don't mind using a high level language like javascript or C# to do this (as those are the langauges I know have video streaming abilities), but I recognize that in order to get to that level of hardware, I may have to use C (which I know pretty well).

I just wondered if there is a certain route I'll have to go in order to accomplish this, like installing Linux (it's a windows 7 computer), or using a specific language, or if there is a library out there that does this already.

The "correct" way of doing this would probably be to do it through a DMA channel, but if it's just a standard video stream, you should be able to cope with the much simpler programmed I/O (PIO), which should give you up to 30MB/s when writing over a PCIe x1 link if done correctly - although this will use more processor resources on your PC than DMA.

I worked on interfacing an FPGA to a PC through PCI express during a preproject to my master's thesis - a pdf version can be found here: http://loejer.dk/files/FORK,%20pdf.zip (the journal2-5 pdf's are probably those of most interest)

It covers the FPGA side (using a Xilinx Spartan3, but it's basically the same with a Spartan6T), and both Windows (XP) and Linux drivers also.